Hi kkcarlton,
The first place I would start your research is the tutorial post here which has the basic information, steps, and guidelines you will need to make the best possible choices.
Post #2 here and the other posts and sources it links to has more information that can help you answer the question of “how safe is safe enough for me?”.
There is also more about the most important parts of the “value” of a mattress purchase in post #13 here but the most important factor is always how well a mattress matches your specific needs and preferences in terms of PPP (Posture and alignment, Pressure relief, and Personal preferences). If you can’t test a mattress in person then I would make sure you have at least talked with a knowledgeable and experienced manufacturer or retailer on the phone so you have some confidence that any mattress you purchase is likely to be a good match for you in terms of PPP and all the other parts of your personal value equation that are important to you. With any purchase you can’t test in person before a purchase I would especially make sure you are familiar with the specifics of any return or exchange options that are available to you (or aren’t available) after a purchase and any costs involved so you are comfortable with the risk involved if your mattress choice doesn’t turn out as well as you hoped.
You have some great options or possibilities in the Grand Rapids area including one of the members of this site. They are listed in post #273 here.
Phoenix